An ink-jet image forming method utilizing ultraviolet ray-curable ink, which can be hardened by an irradiation of an ultraviolet ray, is remarked from the reasons like that there is no limitation of the recording material to be printed thereon, it is superior in the light resistibility, and it is superior in the working safety because the solvent is not included.
In the conventional image forming method, the ink-jet ink has been hardened by a light source such as a high pressure mercury lamp after jetted. However, since the light source generates heat as well as light, problems such like shrinkage of a recording substrate occur when a substrate, which is poor in heat resistance, such as a thermal-shrinkage film, is used as the recording substrate. When the light is emitted onto the recording substrate with keeping a distance between the light source and the recording substrate to respond above-described problems, demerits such as an increase of running cost arise due to a deterioration of energy efficiency.
Further, it is preferable to irradiate the ultraviolet ray as soon as possible after the arrival of the ultraviolet ray-curable ink on the recording substrate to inhibit a bleeding of the formed image. Thus, in the ink-jet printing, the closer the light source to the ink-jet head, the better in this viewpoint. However, if the light source is installed near the ink-jet head, a nozzle clogging is occurred due to the heat of the light source, and the stable printing becomes difficult.